Hexakisazo dyestuffs and their manufacture



Patented Apr. 22, 1941 UNITED HEXAKISAZO DYESTUFFS AND THEIR.MANUFACTURE.

Adolf Krebser, Riehen, near Basel, Switzerland, assignor to the firm J.R. Geigy A. G., Basel,

Switzerland No Drawing. Application October 2, 1939, Serial No. 297,590.In Switzerland October 5, 1938 Claims.

I have found that hexakisazo dyestuffs of the general formula:

wherein D represents a radical with two benzene nuclei, which areconnected either directly or by the atoms or atom groups O-, S, NH-,CH2, SO2-, CH2-CH2, --CH=CH, HN-CO-- etc., A represents a resorcinolradical, B a naphthalene radical containing the azo groups in 1,4position, C a diphenylamine radical and :c signifies a whole number, atleast 4, where by the distribution of the sulphonic acid groups in theradicals B, C and D may vary, are particularly convenient for the dyeingof leather. The new dyestufis defined as above yield "reddish toyellowish brown shades of great dyeing power.

The manufacture of these new dyestuffs may be effected for example bydiazotizing and coupling in alkaline solution two molecules of themonoazo dyestuff CN=NBNH2 with the disazo dyestuff IOH or by couplingone molecule of a tetrazotized di- Example 1 54.3 parts of the monoazodyestufi from diazotized 4'-nitro-4-aminodiphenylamine-Z'-sulphonic acidand 1-naphthylamine-fi-sulphonic acid or the mixture with the 1,7-isomerare dissolved in water with 4 parts of caustic soda lye of 100 per centstrength, mixed with '7 parts of sodium nitrite and allowed to run at 0C. into parts of hydrochloric acid of 30 per cent strength. Thediazotization is completed after a few hours.

The thus obtained diazo compound is added to an aqueous solution of 25.3parts of the disazo dyestuff prepared according to known methods from 1molecule of tetrazotized benzidine-2-monosulphonic acid and 2 moleculesof resorcinol in parts of soda at 0 C. After the coupling is complete,the whole is heated to 50 C. and the dyestuif isolated by means ofcommon salt and hydrochloric acid. The dyestuff filtered and driedconstitutes a dark powder which dissolves in water to a deep red-brown,in concentrated sulphuric acid to a blue solution and dyes leather deepreddish-brown shades. The same dyestufi can also be obtained, butsomewhat more diificultly, if 2 molecules of the monoazodyestufi fromdiazotized 4-nitro-4- aminodiphenyl amine 2'- sulphonic acid andl-naphthylamine-6-sulphonic acid or the mixture with the III-isomer arediazotized and coupled with 2 molecules of resorcinol. The thus obtainedtetrakisazodyestufi is combined in strongly soda-alkaline solution with1 molecule of tetrazotized benzidine -2-monosulphonic acid.

If in this example the used benzidine-Z-monosulphonic acid is replacedby the N,3'-aminobenzoyle-l:4-diamino-benzene-3-sulphonic acid or theN,4'-aminobenzoyle-1:4- diaminobenzene 3- sulphonic acid, a similardyestufl will be obtained.

Example 2 54.3 parts of the monoazo dyestuff from diazotized4'-nitro-4-aminodiphenylamine-2'-sulphonic acid and the mixture ofl-naphthylamine-G- and -7-sulphonic acid are diazotized as described inExample 1 and the diazo compound is added to a solution of 30.6 parts ofthe disazo dyestuff from 1 molecule of tetrazotized4:4'-diaminostilbene-2:2'-disulphonic acid and 2 molecules of resorcinolin water and 40 parts of soda at 0 C. The coupling is completed in a fewhours. The new dyestufi is precipitated with common salt and somehydrochloric acid, filtered and dried. The new dyestuff, a dark powder,dissolves in water with deep reddish-brown, in concentrated sulphuricacid with blue-violet coloration. It dyes leather deep reddish-brownshades.

If instead of the 4:4'-diaminostilbene-2:2-disulphonic acid there areused the 4:4'-diaminodiphenyl-sulphide-2:2'-disulphonic acid, the 4:4-diaminodibenzyl-2:2-disulphonic acid, the 4:4 diamino 3:3 dimethyldiphenylmethandisul phonic acid, the3:3-diamino-4:4-dimethyldiphenylmethandisulphonic acid, the4:4'-diaminodiphenylether-3:3-disu1phonic acid or the 4:4-diamino-diphenylsulphone-disulphonic acid, similar dyestufis areobtained.

Example 3 49.8 parts of the mcnazo dyestufi from diazotlzed4-aminodiphenylamine-Z-sulphonic acid and l-naphthylamine-6- and-7-sulphonic acid are diazotized in an analogous manner to that ofExample 1. The diazo compound is coupled with 29.3 parts of thedisazodyestuff from 1 molecule of tetrazotized 4 :4 -diaminodiphenyl-22-disu1- phonic acid and 2 molecules of resorcinol, which has beendissolved with 40 parts of soda and the necessary quantity of water andadjusted to C. The coupling being achieved, the solution is heated to 500., salted out, filtered and dried. The

new dyestuff is a dark powder, which dissolves in water withyellowish-brown coloration, in concentrated sulphuric acid with dirtyblack-brown coloration and dyes leather deep brown shades.

Example 4 54.3 parts of the monoazo dyestuff from diazotized4'-nitro-4-aminodiphenylamine-2'-sul phonic acid and a mixture ofl-naphthylamine- 6- and -7-sulphonic acid are diazotized, as describedin Example 1, and then coupled at 0 C. with a solution of 29.3 parts ofthe disazo dyestufi from 1 molecule of tetrazotized4:4-diaminodiphenyl-2:2-disulphonic acid and 2 molecules of resorcinol,dissolved in water and 40 parts of soda. After some hours it is heatedto 45 C., salted out, filtered and dried. The new dyestuff, a darkpowder, dissolves in water with brown coloration, in concentratedsulphuric acid with brown-olive coloration and dyes leather deep I brownshad-es.

Example 68.3 parts of the monoazo dyestuif from diazotized 2' nitro4-amino-diphenylamine-4'- phenylsulphone-3"-sulphonic acid (obtainedfrom 4 chloro-3-nitro-diphenylsulphone-3- sulphonic acid by condensationwith 4-acetylaminoaniline and saponification) and the mixture ofl-naphthylamine-6- and -7-sulphonic acid are diazotized as described inExample 1 and then coupled at 0 C. with a solution of 29.3 parts of thedisazo dyestuff from 1 molecule of tetrazotized4:4-diaminodiphenyl-2:Zdisulphonic acid and 2 molecules of resorcinol,dissolved in water and parts of soda. After a few hours the formation ofthe dyestuff is achieved, then it is heated to 0., salted out, filteredand dried. The new dyestufi, a dark powder, dissolves in water withyellow-brown coloration, in concentrated sulphuric acid with dirtyviolet-black coloration and dyes leather beautiful, deep yellow-brownshades.

What I claim is:

1. A process for the manufacture of hexakisazo dyestuffs, comprisingdiazotizing two molecules of a monoazo dyestufl of the formulaC-N=N-B--NH2 and coupling the thus obtained diazo compound in alkalinesolution with one molecule of a disazodyestuff of the formula on on inwhich formulae D represents a radical with two interconnected benzenenuclei selected from the group consisting of twodirectly connectedbenzene nuclei and two benzene nuclei connected by O, S, NH, CH2, S02,CH2.CH2, CH==CH and NHCO, B a naphthalene radical containing the azogroups in 1,4 position and C a diphenylamine radical, care being takenthat at least 4 sulphonic acid groups are present in the molecule of thehexakisazo dyestuff.

2. The hexakisazo dyestufis of the general formula (CN=N-B-N=N-A-N=ND-=N-A--N=NB-N=N-C) (S02H) 2 wherein D represents a radical with twointerconnected benzene nuclei selected from the group consisting of twodirectly connected benzene nuclei and two benzene nuclei connected by O,S, NH, CH2, S02, CH2.CH2, CH=CH and NHCO, A a resorcinol radical, B anaphthalene radical containing the azo groups in 1,4 position, C adiphenylamine radical and :c a whole number, at least 4, havingsulphonic acid groups distributed in the radicals B, C and D, saiddyestuffs being suitable for dyeing leather.

3. The hexakisazo dyestufi as product of condensation of the diazotizedmonoazo dyestufi from diazotized 4'-nitro-4-aminodiphenylamine-2-sulphonic acid and l-naphthylamine-fi-sulphonic acid with the disazodyestuff from 1 molecule of tetrazotized benzidine-2-monosulphonic acidand 2 molecules of resorcinol, said dy-estuff being suitable for dyeingleather.

4. The hexakisazo dyestufi as product of condensation of the diazotizedmonoazo dyestuif from diazotized 4-nitro-4-aminodiphenylamine-2-sulphonic acid and the l-naphthylamine-G- and -7-sulphonic acidmixture with the disazo dyestufi from 1 molecule tetrazotized4:4'-diaminodiphenyl-2 :2'-disulphom'c acid and 2 molecules ofresorcinol, said dyestufi being suitable for dyeing leather.

5. The hexakisazo dyestuii as product of condensation of the diazotizedmonoazo dyestuff from diazotized 2'-nitr0-4-aminodiphenylamine-4-phenylsulphone-3"-sulphonic acid and the l-naphthylamine-fiand-7-sulphonic acid mixture with the disazo dyestufi from 1 molecule oftetrazotized 4:4 diaminodiphenyl 2 :2-disulphonic acid and 2' moleculesof resorcinol, said dyestuff being suitable for dyeing leather.

ADOLF KREBSER.

